This invention relates to apparatus and methods for controlling the extent of rotation of a socket, and, more particularly, relates to apparatus and methods for directly limiting angular displacement of a socket to a selected extent in excess of about 360xc2x0.
Currently the assembly of equipment requires a vast array of different size fittings and/or other threaded connectors, each requiring application of a set amount of torque for proper securement.
Some presently utilized tool systems, for application in manipulating hydraulic fittings for example, employ transducers with electrical motor controlled nut runners capable of sensing the torque being applied through a socket to a tube nut to control torque application. Heretofore known hydraulic and/or pneumatic tools have utilized spring biased clutches to determine when a desired torque application has been reached. In such cases, sensing of a desired torque application to the threaded connector results in shut-off of power to the driver and thus cessation of motive force to the drive head having the socket located therein.
While widely utilized, these systems require that a specific driver be matched to an individual drive head for each nut size and torque application requirement. Moreover, accuracy of torque application in heretofore known systems is difficult to control due to the inertia of the moving gears and socket employed by the drive heads of such systems. Thus, most conventional pneumatic, hydraulic and/or electric tool systems employing heretofore known torque control schemes allow the drive head gears and/or socket to xe2x80x9ccoastxe2x80x9d, or rotate, beyond the point of ideal torque application after power application to the tool ceases.
Many threaded connector manufacturers have determined that the best way to secure their fasteners (tube nuts for high pressure fittings, for example) is to first hand tighten them and then continue beyond this initial set point by a selected additional angular displacement (referred to often as a specific additional number of xe2x80x9cturnsxe2x80x9d). For example, it is quite common for tube nut torque specifications to be expressed as xe2x80x9chand tight plus one and one quarter turnsxe2x80x9d (i.e., 450xc2x0 of additional angular displacement of the nut beyond finger tight).
As may be appreciated, the amount of torque required to achieve this specified additional angular displacement for properly securing a fastener varies greatly depending on the size of the fastener thus further complicating torque application control in the field. For example, a small fastener might require 30 foot-pounds to achieve the correct additional angular displacement, while a large fitting could require 130 foot-pounds or more to achieve the same degree of additional angular displacement. In addition, each fitting, and particularly fittings of different size, will present different tightening resistance characteristics, the resistance to tightening building rapidly after the fitting has been hand tightened. Such torque application differences require provision of multiple drive tools in the field. Moreover, the unpredictability of actual operational behavior of any specific fastener leads to frequent fastener failure in many applications, requiring reinstallations and thus increasing the expense of operations.
Since manufacturers often suggest or specify correct fitting application by a number of xe2x80x9cturnsxe2x80x9d (or angular displacement) after finger tightening, it would be desirable to more directly control angular displacement instead of torque application. If driver power is adequate, such control would overcome the resistance of the fastener no matter the degree, and precisely stop fastener rotation at the exact selected displacement. To date, however, such direct angular displacement control system for use with pneumatic, hydraulic or electric powered threaded connector drive tools has not been suggested or achieved acceptance.
Finally, it would be desirable for the means of controlling correct application and tightening of threaded connectors to be built for association with the drive head of the tool and not into the driver so that any of the variety of drivers available could be utilized with the head. Further improvements in this regard could also still be utilized.
This invention provides apparatus and methods for precisely limiting angular displacement of a socket independent of particular operational torque application requirements, and in particular where extent of socket rotation desired is about equal to or exceeds 360xc2x0. The apparatus is configured to operate in at least one, and preferably both, directions of rotation, is adaptable for use with a variety of drive head sizes an/or configurations and thus driver applications (i.e., fluid or electrical drives), and is not-susceptible to socket xe2x80x9ccoastingxe2x80x9d beyond the desired angular displacement and thus torque application. The apparatus operates precisely independent of particular size, type, or exhibited rotational resistance characteristics of a fastener being manipulated by the socket by directly controlling angular displacement of the socket rather than torque application.
The apparatus includes a rotatable structure having a circumferentially projecting construct rotatable through a path of rotation, the rotatable structure associable with a socket drive assembly so that rotation of the rotatable structure and rotation of the socket at the assembly are coincident. A unit is maintained adjacent to the rotatable structure, the unit having a first portion movable into and out of the path of rotation and a second portion at the path of rotation spaced from the first portion in a down-path direction corresponding to a first direction of rotation of the rotatable structure. The first portion interacts with the construct of the rotatable structure to halt rotation of the rotatable structure in the first direction of rotation when the first portion is in the path of rotation. The second portion of the unit is contactable by the construct of the rotatable structure moving in the first direction of rotation to effect movement of the first portion relative to the path of rotation.
In a now preferred embodiment of the apparatus, the construct of the rotatable structure includes first and second circumferentially projecting formations axially differentiated so that the formations rotate in substantially different planes through the path of rotation. The unit includes a biased member having the first portion thereat, a surface of the biased member being contactable by the first formation of the rotatable structure moving in a reverse direction of rotation when the biased member is in the path of rotation causing movement of the biased member against its bias relative to the path of rotation. The first portion interacts with the first formation of the construct of the rotatable structure to halt rotation in the first direction of rotation. The second portion of the unit includes a lobe positioned for contact by the second formation of the rotatable structure and a release positioned to capture and hold the first portion of the unit and to release the first portion responsive to contact of the lobe allowing biased movement of the first portion into the path of rotation.
The apparatus is preferably configured for limiting angular displacement of a slotted socket to a selected extent about equal to or in excess of 360xc2x0 in both forward and reverse directions of rotation. In this case, the circumferentially projecting construct of the rotatable structure has first and second spaced surfaces rotatable through the path of rotation, an arrangement provided for limiting rotation of the rotatable structure to a selected extent about equal to or in excess of 360xc2x0 in either of the forward or reversed directions of rotation.
The arrangement, a unitary element or multiple elements, includes first and second barrier portions and first and second actuating portions, the first barrier portion movable into and out of the path of rotation and the first actuating portion at the path of rotation spaced from the first barrier portion in a down-path direction corresponding to the forward direction of rotation of the rotatable structure. The first barrier portion interacts with the first surface of the construct of the rotatable structure to halt rotation of the rotatable structure in the forward direction of rotation when the first barrier portion is in the path of rotation, the first actuating portion contactable by the construct of the rotatable structure moving in the forward direction of rotation to effect movement of the first barrier portion into the path of rotation.
The second barrier portion is movable into and out of the path of rotation with the second actuating portion at the path of rotation spaced from the second barrier portion in a down-path direction corresponding to the reversed direction of rotation of the rotatable structure. The second barrier portion interacts with the second surface of the construct of the rotatable structure to halt rotation of the rotatable structure in the reversed direction of rotation when the second barrier portion is in the path of rotation, the second actuating portion contactable by the construct of the rotatable structure moving in the reversed direction of rotation to effect movement of the second barrier portion into the path of rotation.
The method of this invention, for controlling rotation of a socket to a selected extent in excess of about 360xc2x0, includes effecting coincident rotation of the socket and a cam having a surface oriented across a path of rotation. The cam is rotated past a barrier and into contact with a lobe to effect movement of the barrier into the path of rotation after passage of the surface of the cam. Cam rotation is continued until contact between the surface and the barrier halts rotation of the cam and thereby rotation of the socket, whereafter cam rotation is reversed to thereby effect movement of the barrier out of the path of rotation.
It is therefore an object of this invention to provide apparatus and methods for precisely controlling angular displacement of a socket.
It is another object of this invention to provide apparatus and methods for directly controlling angular displacement of a socket independent of particular operational torque application requirements.
It is another object of this invention to provide apparatus and methods for controlling angular displacement of a socket where extent of socket rotation desired equals or exceeds 360xc2x0.
It is another object of this invention to provide apparatus for controlling angular displacement of a socket that is configured to operate in at least one, and preferably both, directions of rotation, is adaptable for use with a variety of drive head sizes an/or configurations and thus driver applications, and is not susceptible to socket xe2x80x9ccoastingxe2x80x9d beyond the desired angular displacement and thus torque application.
It is still another object of this invention to provide apparatus and methods for controlling angular displacement of a socket independent of particular size, type, or exhibited rotational resistance characteristics of a fastener being manipulated by the socket.
It is another object of this invention to provide an apparatus for limiting angular displacement of a socket, the socket held in an assembly including a drive for effecting rotation of the socket, the apparatus including a rotatable structure having a circumferentially projecting construct rotatable through a path of rotation, the rotatable structure associable with the assembly so that rotation of the rotatable structure and rotation of the socket are coincident, and a unit maintained adjacent to the rotatable structure, the unit having a first portion movable into and out of the path of rotation and a second portion at the path of rotation spaced from the first portion in a down-path direction corresponding to a first direction of rotation of the rotatable structure, the first portion interacting with the construct of the rotatable structure to halt rotation of the rotatable structure in the first direction of rotation when the first portion is in the path of rotation, the second portion of the unit contactable by the construct of the rotatable structure moving in the first direction of rotation to effect movement of the first portion relative to the path of rotation.
It is still another object of this invention to provide an apparatus for limiting angular displacement of a slotted socket to a selected extent about equal to or in excess of 360xc2x0, the slotted socket held in an assembly including a drive for effecting rotation of the socket, the apparatus including a rotatable structure having a circumferentially projecting construct with first and second spaced surfaces and rotatable through a path of rotation, the rotatable structure having a mount associable with the assembly so that rotation of the rotatable structure in either of forward or reversed directions is coincident with socket rotation in either of clockwise or counterclockwise directions, and rotation limiting means for limiting rotation of the rotatable structure to a selected extent about equal to or in excess of 360xc2x0 in either of the forward or reversed directions of rotation, the rotation limiting means including first and second barrier portions and first and second actuating portions, the first barrier portion movable into and out of the path of rotation and the first actuating portion at the path of rotation spaced from the first barrier portion in a down-path direction corresponding to the forward direction of rotation of the rotatable structure, the first barrier portion interacting with the first surface of the construct of the rotatable structure to halt rotation of the rotatable structure in the forward direction of rotation when the first barrier portion is in the path of rotation, the first actuating portion contactable by the construct of the rotatable structure moving in the forward direction of rotation to effect movement of the first barrier portion into the path of rotation, the second barrier portion movable into and out of the path of rotation and the second actuating portion at the path of rotation spaced from the second barrier portion in a down-path direction corresponding to the reversed direction of rotation of the rotatable structure, the second barrier portion interacting with the second surface of the construct of the rotatable structure to halt rotation of the rotatable structure in the reversed direction of rotation when the second barrier portion is in the path of rotation, the second actuating portion contactable by the construct of the rotatable structure moving in the reversed direction of rotation to effect movement of the second barrier portion into the path of rotation.
It is yet another object of this invention to provide a method for controlling rotation of a socket to a selected extent in excess of about 360xc2x0 includes the steps of effecting coincident rotation of the socket and a cam having a surface oriented across a path of rotation, rotating the cam past a barrier and into contact with a lobe to effect movement of the barrier into the path of rotation after passage of the surface of the cam, continuing cam rotation until contact between the surface and the barrier halts rotation of the cam and thereby rotation of the socket, and reversing cam rotation to thereby effect movement of the barrier out of the path of rotation.
With these and other objects in view, which will become apparent to one skilled in the art as the description proceeds, this invention resides in the novel construction, combination, arrangement of parts and method substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that changes in the precise embodiments of the herein disclosed invention are meant to be included as come within the scope of the claims.